Battery Drain... PLEASE help!

Here's the deal, I have a 2006 H3 with the monsoon sound system, a 12" Kicker with a Dual amplifier (the amp runs the correct 150 watts at 4 ohms bridged), a toggle switch that controls the power to the amplifier in the head unit, and a CB radio. The battery began to die so I disconnect the power line to the amplifier and to the monsoon sub-woofer. However, it happened again a few days later. I checked the amps coming from the battery's ground wire, and I discovered a parasitic drain of 1.72 amps :whaamaking sure everything electrical was off). I disconnected the CB radio from the fuse box and still had a 1.72 amp draw. The only time I noticed a significant amount of change was when I removed fuse 13 (radio, heating, ventilation, air conditioning display). The multimeter read ~0.65 amps with that fuse removed. I tried several others, but still couldn't find the culprit. Any other suggestions on what might be drawing power when the car is off? I really don't want to go fuse by fuse to find the evil bastard!:smash

Thanks in advance!

Only correct way is to go fuse-by-fuse. Does not take that long, so long as you have a good pair of very small needle nose pliers.
But what is causing the large drain in the radio circuit?

You are allowing the system go into sleep mode? In other words, makes sure you don't shut down the engine and immediately start checking draw. The computer take up to 20 minutes to go into sleep mode, and until that time, they will draw a lot more juice. Once in sleep mode the draw should be around 55-75 milliamps.

Seems I remeber some having this complaint and disconnecting the onstar module fixed it.
To get to it remove the center panel. Look down under the radio. And the onstar box is at the bottom of the opening. I believe it has 2 connectors going to it.

Deactivated onstar will cause a drain. Also, listen to F5 as disconnecting battery cable to inser amp meter will not show correct for at least 20 minutes or so until system is in sleep mode, this is likely why you see high drain at first.

Does it take 20 minutes from the time I disconnect the battery, or 20 minutes after the car is off? I checked it after it had been sitting for about a day. I'm definitely going to try and find the OnStar module. There was another thread that mentioned a tracking system installed by the previous owner and that turned out to be the parasite. I can see how the OnStar device could be doing the same thing.
Thanks for the quick responses!:thumbsup

southernhummerguy said:

Does it take 20 minutes from the time I disconnect the battery, or 20 minutes after the car is off? I checked it after it had been sitting for about a day. I'm definitely going to try and find the OnStar module. There was another thread that mentioned a tracking system installed by the previous owner and that turned out to be the parasite. I can see how the OnStar device could be doing the same thing.
Thanks for the quick responses!:thumbsup

Click to expand...

20 minutes after the ignition has been turned off. Depending on the year, all the modules go into sleep mode. Later model vehicles might have all the modules go into a really deep sleep mode but the BCM will just go into sleep mode. When the ignition is turned on, or a remote signal is received, the modules will come alive or in the second case, the BCM will come alive then wake up the other modules. This all happens in milliseconds.

As for tracking devices, there are aftermarket ones that people do purchase to track their kids, their wife, husband or girl friends. But the Onstar module is like all other modules on the buss, it should go into sleep mode. If it doesn't it is a fault with the module, and all my time at GM, never heard of any major problem with the Onstar module. In fact, in the majority of claims we saw with the parasitic drain at or near 2 amps it was either the radio or an HVAC module.

The radio has only one circuit, that is a B+, there is no ignition on circuit to the stock radio. The BCM supplies the turn On signal via the buss. So if you pulled that fuse and it dropped over an amp, the it is time to start disconnecting the components on that circuit.

Looking at the wiring schematic for a 2006 H3 (all other years should be the same), fuse 13 feeds the HVAC control head and the radio. Time to pull the panel, and disconnect each component and see which one drops the current down by the same number you had when you pulled the fuse. If the high amp draw does not drop, then it is time to look for another item connected to the orange wire to terminal B1 (Light grey, 24 pin connector) on the radio and terminal B (grey, 12 pin connector) on the HVAC control module. When I say "other wire" I mean one added by someone other than the original wiring from the factory. If this is a used vehicle, then I would look for some wiring taps into that orange wire nearby the radio, HVAC module. It is a pretty easy wire to access if someone wants B+ for another component inside the passenger compartment (CB maybe?).

Once you solve this 1+ amp draw, the it will be time to find the other draw....

If you still want to check out the Onstar module then it is easy do disconnect if you are already in the radio/HVAC area. If you want to pull the fuse. it is not located in the junction block. The Onstar fuse is located inline with the battery positive cable and should be located just behind the battery, just in front of the junction block. (NOTE: The Onstar fuse is also the fuse for the power circuit of the XM (Digital) receiver.)

Onstar/XM fuse circled

If you disconnect the battery while all the modules are sleeping, and then insert your ammeter thus reconnecting the battery, will that wake up the modules?

Very good point. You're making me think.

I can say the procedures we used at GM/Saturn were to charge the battery to full capacity, then make sure the vehicle starts and runs, turn off ignition, and then connect the ammeter and walk away for a cup or two of coffee, get the tools for pulling fuses, etc., and do other things. We usually did not get back to the vehicle for a good thirty minutes or more.

I would want to think that the wake up is a door switch, remote signal or the ignition key on/resistor signal; however, I cannot say for certain a sudden drop in B+ then a B+ signal would not wake up the BCM.

I guess to be safe, it would be advisable to wait twenty after the ammeter (or shunt if no large current ammeter is available) is installed. But also, make sure the battery is fully charged, or you might get a dead battery while pulling/installing fuses and this could screw up a fault.

UPDATE (since the holidays had me away): I decided to do it the "proper" way. I pulled all of the fuses, and I thought I found the problem fuse, however, I discovered a bigger problem:eek. When I went to double check by putting the fuse back in, the multi-meter still read the same amperage (oh yea, original reading = 1.72 and it went down to 0.08). So I marked the fuse and continued pulling all of the fuses. The new problem I discovered is the drain occurs in intervals because as I continued pulling the fuses the amperage fluctuated between 1.72 and 0.08. I watched the meter with all of the fuses in for a (very long) period of time and sure enough something is using battery power periodically:banghead:. I made sure to wait 30 minutes after popping the hood to make sure everything was in sleep mode. Any suggestions.... please!

This interval.... is it a regular interval like, say, every 30 minutes or something similar? Edit: Does this periodic drain happen with *all* fuses pulled?

Which fuse was the one you thought was the problem fuse?

The interval is around 5 minutes. It reads 1.72 amps. for five minutes, then 0.08 amps. for five minutes. I haven't tried it with all the fuses pulled. I should mention that I have only pulled fuses, I did not pull any of the relays or diodes or fuses 82-85. The fuse that seemed to be the problem was fuse 42 (TRLR BCK/UP).

Sounds like you need to pull a fuse and wait for the interval then repeat until you don't see a change on the interval.